perpetual motion

perpetual motion

n.

The hypothetical continuous operation of an isolated mechanical device or other closed system without a sustaining energy source.

perpetual motion

n

1. Also called: perpetual motion of the first kind motion of a hypothetical mechanism that continues indefinitely without any external source of energy. It is impossible in practice because of friction

2. Also called: perpetual motion of the second kind motion of a hypothetical mechanism that derives its energy from a source at a lower temperature. It is impossible in practice because of the second law of thermodynamics

perpet′ual mo′tion

n.

the motion of a theoretical mechanism that, without any losses due to friction or other forms of dissipation of energy, would continue to operate indefinitely at the same rate without any external energy being applied to it.

There was not the slightest necessity for the greater portion of the labour performed by the old lady: but she seemed to work from some irresistible impulse; her limbs continually swaying to and fro, as if there were some indefatigable engine concealed within her body which kept her in perpetual motion.

I can no more tell you the whys and wherefores of myself than I can lift myself up by the waistband and carry myself into the next county, as some one challenged a speculator in perpetual motion to do.

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